Binding of local anesthetics and various cations to cellular membranes and myelin is being investigated to determine if anesthetics interact with membrane sites which normally bind cations such as Na ion, K ion and Ca2 ion. Binding is measured utilizing radioactive tracers. Interactions of local anesthetics and various membrane components, isolated from membranes such as as myelin, are also being investigated utilizing radioisotopes and fluorescent probes. Myelin proteins have been isolated and their interactions with cations and local anesthetics studied. Reconstitution of membranes from pure lipids and myelin proteins has been undertaken with the view to determining the localization of structural proteins within myelin as compared to the reconstituted membranes.